Friday, September 22, 2006

DDT in America?

Someone I respect posted the following comment after our recent blog entry regarding the World Health Organization approving the use of DDT to control malaria. “ The DDT ban still makes sense here in the States where the nonexistent threat of malaria does not outweight the predator-death externality.”

I have to disagree with this sentiment. First the idea that malaria is a nonexistent threat simply is not true. Yes, to a large degree it has be erradicated and it should be noted that was in no small measure due to the use of DDT. I well remember the “fogger” trucks that drove through our neighbourhood spraying a white fog laced with DDT during the summer months. It was a mosquito abatement program. We kids used to run through the fog. The smell wasn’t entirely unpleasant and we knew once we got it on our skin nd clothes it kept the mosquitoes away. And it was fun. And to this day I don’t worry one iota about it because I’ve seen the studies and DDT is safe to humans. It isn’t safe to mosquitoes but I confess I don’t really care much for them.

According to the Centers for Disease Control “Between 1957 and 2003, in the United States, 63 outbreaks of locally transmitted mosquito-borne malaria have occurred...” i wouldn’t call 63 oubreaks “nonexistant”.

In additon they remind us that the two species of Anopheles mosquitoes that have spread malaria in the past in the US “are still widely prevalent; thus there is a constant risk that malaria could be reintroduced in the United States.’”

Then there is denque hemorrhagic fever. Not a particularly pleasant illness. The mosquioe that carries it prevalentin the American south. Now the United States is just barely north of infested areas. The CDC says there is a “small risk of dengue outbreaks in the continental United States” because “two competent mosquito vectors... each [of which] could transmit dengue viruses” are found in the US.They also report that “this type of transmission has been detected six times in the last 25 years in south Texas”. Denque is on the rise and the chance of an outbreak in the US increases yearly.

There is also West Nile virus. Sounds exotic and unAmerican but quite common in the US and also spread by mosquitoe. Look at the map above to get some idea of how widespread it is.

These are just some mosquitoe-borne illnesses in the United States. So I’m not so sure your case is as strong as you thought.